phpBB.com might want to add a CPF to to let members add one of the many Stack Exchange sites' member profile URIs. I'm not asking to have this in phpBB as a product/software, but only on this very website itself (hence the WEBSITE ticket, not a PHPBB ticket). Given that not few members are developers or power users it could be a quite useful custom profile field.

Just like a GitHub Account CPF already exists.